Blue-green luminescent silicon nanocrystals fabricated by nanosecond pulsed laser ablation in dimethyl sulfoxide

Abstract

In this work, stable blue-green luminescent colloidal silicon nanocrystals (SiNCs) are fabricated by nanosecond pulsed laser ablation of a silicon target in dimethyl sulfoxide (DMSO). Transmission electron microscopy and X-ray diffraction analysis have shown the formation of spherical silicon nanocrystals in the colloid with size range of 2-5 nm. Our results show that the DMSO stabilizes the silicon nanocrystals via oxide formations on the nanocrytals surfaces by a simple route of laser ablation and a schematic representation of the process is suggested. The colloid exhibits strong blue luminescent emissions in the spectral range of 455-465 nm when excited at wavelengths near the direct band gap of the silicon nanocrystal. The luminescent emission band shifts to longer wavelengths (green light) if the excitation wavelength increases toward the indirect band gap of the SiNCs. The oxidized SiNCs with quantum confinement effects are shown to be responsible for visible photoluminescence of the colloid. The observed blue-green emission of the colloid makes it a good candidate for display, solid-state lighting and biological luminescent based devices.

Resolving the source of blue luminescence from alkyl-capped silicon nanoparticles synthesized by laser pulse ablation

“…1c) is significantly different from the as-ablated Si NPs (Fig. 17,23,37,38 The PL of the separated Si NPs, centred at 335 nm (3.64 eV), is consistent with that of chemically synthesized alkyl-capped Si NPs, 8,31,33 where emission in the ~330-360 nm region was attributed to be a result of electron-hole recombination across the direct Γ 4 eV). 17,23,37,38 The PL of the separated Si NPs, centred at 335 nm (3.64 eV), is consistent with that of chemically synthesized alkyl-capped Si NPs, 8,31,33 where emission in the ~330-360 nm region was attributed to be a result of electron-hole recombination across the direct Γ 4 eV).…”

Solvent dependent optical limiting and thermo-optical response of silicon nanoparticle colloids

“…The TEM image and size distribution of SiNCs suspension prepared in the DMSO have been reported in Ref. [15]. Average SiNCs radius is found to be about 1.9 ± 0.8 nm and 3.5 ± 1.5 nm in the water and DMSO respectively.…”

“…The detail of the experimental procedure has been given in reference [15]. The volume fractions of the prepared SiNC colloids in the water and DMSO were 9.0 × 10 −6 and 8.2 × 10 −6 , respectively.…”

Silicon nanoparticles from pulsed laser ablation

“…It was demonstrated that SiNCs produced in deionized water were much smaller when compared to the ones in polymer (Švrček and Kondo 2009). Mansour et al produced SiNCs with average size 3.5 nm by PLAL by using dimethyl sulfoxide (DMSO) as the liquid medium (Mansour et al 2012). These studies indicate that the liquid medium is quite important for the size of SiNCs, and the other suitable solvents for the production of SiNCs should be investigated in detail.…”

“…SiNCs are produced in the liquid environment by laser ablation. The silicon volume fraction, ϕ V inside the liquid that is ablated inside is calculated by following Equation (9.3) (Mansour et al 2012):…”